Erosion-resistant insert for flow measurement devices

ABSTRACT

An erosion-resistant insert is provided for a flow measurement device having a fluid displacement member. The insert includes a flange and a sleeve extending axially from the flange. The sleeve may be inserted into a recess machined into a fluid conduit of the fluid measurement device to protect the inner wall of the conduit. The insert maintains a property of the flow measurement device.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.13/007,555, entitled “Erosion-Resistant Insert for Flow MeasurementDevices”, filed Jan. 14, 2011, which is herein incorporated by referencein its entirety.

BACKGROUND

This section is intended to introduce the reader to various aspects ofart that may be related to various aspects of the present invention,which are described and/or claimed below. This discussion is believed tobe helpful in providing the reader with background information tofacilitate a better understanding of the various aspects of the presentinvention. Accordingly, it should be understood that these statementsare to be read in this light, and not as admissions of prior art.

Transport of fluids, such as in oil and gas systems, power generationsystems, etc., relies on a variety of components and devices. Forexample, fluids may be transported through a complex network of pipes,fittings, and processing equipment. Such networks may be a part ofpipelines or other transportation structures to transport the fluid froma source to a destination, such as further transportation systems orstorage facilities. Such pipelines or other transportation structuresmay include pressure control, regulation, and safety devices, which mayinclude valves, actuators, sensors, and electronic circuitry.

It may be desirable to measure the flow rate of the fluid in suchsystems. One particular type of flow rate measurement device may bereferred to as a differential pressure meter. A differential pressuremeter places a fluid displacement member centrally within the flow pathof a fluid. As the fluid flows around the displacement member, the fluiddisplacement member causes differential pressure in the fluid. Thedifference in pressure may be measured via taps disposed on the upstreamand downstream portions of the fluid displacement member. The flow rateof the fluid may be determined from the difference in pressure.

The differential pressure meters are designed for use with andcalibrated for specific types of fluids and flow rate ranges. Duringoperation, the actual flow rate of a fluid may be outside the rangemeasured by the meter, and, the type or composition of the fluid mayalso change.

BRIEF DESCRIPTION OF THE DRAWINGS

Various features, aspects, and advantages of the present invention willbecome better understood when the following detailed description is readwith reference to the accompanying figures in which like charactersrepresent like parts throughout the figures, wherein:

FIG. 1 is a diagram of a differential pressure flow meter in accordancewith an embodiment of the present invention;

FIG. 2 is a partial cross-section of the meter of FIG. 1 in accordancewith an embodiment of the present invention;

FIGS. 3A and 3B are cross-sections of an area ratio changer used withthe differential pressure flow meter of FIG. 2 in accordance with anembodiment of the present invention;

FIG. 4 is a cross-section of the area ratio changer of FIGS. 3A and 3Bin accordance with an embodiment of the present invention;

FIG. 5 is a perspective view of the area ratio changer of FIGS. 3A and3B in accordance with an embodiment of the present invention;

FIGS. 6A and 6B are cross-sections of an area ratio changer having ashort sleeve and used with the differential pressure flow meter of FIG.2 in accordance with an embodiment of the present invention;

FIG. 7 is a cross-section of the area ratio change of FIGS. 6A and 6B inaccordance with an embodiment of the present invention;

FIG. 8 is a perspective view of the area ratio changer of FIGS. 6A and6B in accordance with an embodiment of the present invention;

FIGS. 9A and 9B are cross-sections of an area ratio changer used with aPitot tube in accordance with an embodiment of the present invention;and

FIGS. 10A and 10B are cross-sections of an area ratio changer used witha vortex meter in accordance with an embodiment of the presentinvention;

FIG. 11 is a partial cross-section of the meter of FIG. 1 having anerosion-resistant beta ratio changer in accordance with an embodiment ofthe present invention;

FIG. 12 is a partial cross-section of the meter of FIG. 1 having arecess for receiving an erosion-resistant insert in accordance with anembodiment of the present invention;

FIG. 13 is a partial cross-section of the meter of FIG. 12 with anerosion-resistant insert in accordance with an embodiment of the presentinvention;

FIG. 14 is a cross-section of the erosion-resistant insert of FIG. 13 inaccordance with an embodiment of the present invention;

FIG. 15 is a perspective view of the erosion-resistant insert of FIG. 13in accordance with an embodiment of the present invention;

FIG. 16 is a cross-section of an erosion-resistant insert in accordancewith another embodiment of the present invention;

FIG. 17 is a perspective view of an erosion-resistant insert inaccordance with an embodiment of the present invention; and

FIG. 18 is a flowchart for installing an erosion resistant insert in afluid measurement device in accordance with an embodiment of the presentinvention.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

One or more specific embodiments of the present invention will bedescribed below. These described embodiments are only exemplary of thepresent invention. Additionally, in an effort to provide a concisedescription of these exemplary embodiments, all features of an actualimplementation may not be described in the specification. It should beappreciated that in the development of any such actual implementation,as in any engineering or design project, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which may vary from one implementation toanother. Moreover, it should be appreciated that such a developmenteffort might be complex and time consuming, but would nevertheless be aroutine undertaking of design, fabrication, and manufacture for those ofordinary skill having the benefit of this disclosure.

Embodiments of the present invention include a beta ratio changer (alsoreferred to as area ratio changer) for various metering devices. Forcertain flow meters having a beta ratio, embodiments of the presentinvention may be referred to as a beta ratio changer. For other metersthat do not rely on a beta ratio, embodiments of the present inventionmay be referred to as an area ratio changer. In one embodiment, the betaratio changer may be used to change the beta ratio of a differentialpressure flow meter having a fluid displacement member disposed in aconduit. The beta ratio changer may also be formed of anerosion-resistant material to protect the inner walls of a conduit ofthe flow meter from a fluid. Other embodiments of the invention includean erosion-resistant insert for the flow meter. The erosion-resistantinsert may maintain the diameter of a conduit of the flow meter andprotect the inner walls of the conduit from a fluid. Theerosion-resistant insert may also maintain the beta ratio (or arearatio) of the flow meter. In some embodiments, a recess (e.g., anannular recess) may be machined in a conduit of a body of a flow meterto receive the erosion-resistant insert. The sleeve of theerosion-resistant insert (and, in some embodiments, the flange of theinsert), may be formed from an erosion-resistant material.

FIG. 1 depicts a system 10 having a flow measurement device, e.g., adifferential pressure flow meter 12, in accordance with an embodiment ofthe present invention. The differential pressure meter 12 includes ameter body 14 having a conduit 16 through which fluid may flow. A fluiddisplacement member 18 may be centrally disposed in the conduit 16 andsuspended from the conduit 16 via a support 19. Fluid may flow throughthe conduit 16 and over the fluid displacement member 18 in thedirection indicated by arrows 20. The fluid may flow into the conduit 16of the meter 12 either directly or indirectly from a source 24. Forexample, the source 22 may be a source of oil, natural gas (such as coalbed methane), steam, or any other suitable fluid. The meter body 14 mayinclude flanges 26 to provide for installation in a pipeline (e.g.,between pipe sections) or other transportation structure. The flanges 26may be secured to other structure via bolts, welds or any other suitabletechniques.

As the fluid flows through the conduit 16, the fluid displacement causedby the fluid displacement member 18 may introduce a difference inpressure between the upstream fluid (e.g., upstream of the member 18)and the downstream member (e.g., downstream of the member 18). In someembodiments, the fluid displacement member 18 may have one or morefrustum portions, conical portions, or any other shaped portionssuitable for creating a pressure differential in the fluid. In yet otherembodiments, multiple fluid displacement members may be included in themeter body 14 of the flow measurement device 12. In some embodiments,the fluid displacement member 18 may be removably attached by and to thesupport 19 such that the member 18 may be removed and/or replaced. Inother embodiments, the member 18 may be permanently secured by thesupport 19, such as by welding.

The meter body 14 may include an upstream pressure tap 28 in fluidcommunication with the conduit 16 and a downstream pressure tap 30 influid communication with the interior of the fluid displacement member18 and the downstream portion of the conduit 16, such as via hollowregion 32 (e.g., interior passage) of the support 19 and hollow region31 (e.g., interior passage) of the fluid displacement member 18. Thedifference in pressure measured at the upstream tap 28 and thedownstream tap 30 may be used to determine the flow rate of the fluidflowing through the conduit 16.

The upstream tap 28 and downstream tap 30 may be coupled to a valvemanifold 34. Valves 35 may be coupled between the manifold 34 and thetaps 28 and 30. The manifold 34 may be coupled to a transmitter 36 thatrecords the differential pressure signal generated by the meter 12 andprovides an output (e.g., an analog or serial output) to a computer 38,such as a flow computer or data control system having memory 39 andprocessor 40. The manifold 34 isolates the transmitter 36 from theprocess fluid and may enable maintenance and calibration of thetransmitter 36. It should be appreciated that the system 10 may includeany other devices suitable for controlling and/or monitoring the fluidflowing through the conduit 16, such as a resistance temperaturedetector (RTD).

FIG. 2 depicts a cross-section of the meter 12 illustrating the fluiddisplacement member 18 having an upstream frustum 42 and a downstreamfrustum 44 in accordance with an embodiment of the present invention. Asillustrated, the upstream frustum 42 comprises a diverging cone relativeto the fluid flow direction 20, whereas the downstream frustum 44comprises a converging cone relative to the fluid flow direction 20. Theinterface between the upstream frustum 42 and downstream frustum 44forms a peripheral edge 45 (also referred to as cantilevered edge). Asshown in FIG. 2, the downstream frustum 44 may include a hole 46connected to hollow region 32 to enable fluid communication between thedownstream tap 30 and the fluid downstream from the member 18. The shapeof the member 18 may be designed to reshape the fluid velocity provideupstream of the member 18, creating a pressure drop between thedownstream and upstream portions of the fluid in the conduit 16.

The calibration and accurate measurement of the meter 12 depends in parton the “beta ratio” (also referred to as area ratio). The beta ratiorefers to the ratio between the diameter of the peripheral edge 45 andthe diameter of the conduit 16. Additionally, the slope of thedownstream frustum may be referred to as a “beta angle.” The beta ratiomay be determined as follows:

$\begin{matrix}{\beta = \frac{\sqrt{D^{2} - {d\; 2}}}{D}} & (1)\end{matrix}$Where:

-   β=the beta ratio;-   D=the diameter of the conduit 16; and-   d=the diameter of the downstream frustum at the peripheral edge.

After determination of the Beta ratio, the mass flow rate of the fluidmay be determined as follows:qm=N ₁ CdEvY(βD)²√{square root over (ρ_(t,p) ΔP)}  (2)Where:

-   qm is the mass flow rate;-   N₁ is a units constant;-   Cd is a discharge coefficient that may determined during calibration    of the meter;-   p_(t,p) is the fluid density at flowing conditions;-   ΔP is the differential pressure (that may be determined from data    received the upstream tap 28 and downstream tap 30;

For Equation 2, Y may have a value of 1 for incompressible fluids. Forcompressible fluids, Y may be experimentally determined or calculated byvarious techniques, such as according to the following equation:

$\begin{matrix}{Y = {1 - {\left( {0.41 + {0.35\;\beta^{4}}} \right)\frac{\Delta\; P}{k}}}} & (3)\end{matrix}$Where:

-   k is the gas isentropic exponent.

For Equation 2, Ev may be determined from the beta ratio (β) as follows:

$\begin{matrix}{{Ev} = \frac{1}{\sqrt{1 - \beta^{4}}}} & (4)\end{matrix}$

After determination of the mass flow rate, volumetric rates of the fluidmay be determined. For example, the volumetric flow rate at flowingconditions (also referred to as “gross” or “actual” flow rates) may bedetermined as follows:

$\begin{matrix}{{qv} = \frac{qm}{\rho_{t,p}}} & (5)\end{matrix}$Where:

-   qv is the volumetric flow rate at flowing conditions.

Similarly, the volumetric flow rate at based conditions (also referredto as “standard” flow rates) may be determined as follows:

$\begin{matrix}{{Qv} = \frac{qm}{\rho_{b}}} & (6)\end{matrix}$Where:

-   Qv is the volumetric flow rate at base conditions; and-   ρ_(b) is the fluid density at base conditions.

It should be appreciated that changes in temperature, Reynolds number ofthe fluid, or any other parameter may be compensated for in the aboveequations by using suitable correction techniques.

The fluid flowing from the source 24, such as a well, may be producedunder gradually less pressure as the amount of fluid in the welldecreases. In such an embodiment, the originally designed and calibratedbeta ratio of the meter 12 may have a measurable range unsuitable forthe lower flow rate of the fluid. Additionally, the meter 12 may bemoved and used in a new system having a different fluid flow rate or adifferent type of fluid.

FIGS. 3A and 3B depict a beta ratio changer 50 used with the meter 12 inaccordance with an embodiment of the present invention. The beta ratiochanger 50 may include an annular sleeve 52 and a flanged portion 54.The annular sleeve 52 extends axially from the flanged portion 54. Thesleeve 52 includes an inner diameter (D_(S)) that is smaller than theinner diameter (D_(C)) of the conduit 16. The sleeve 52 of the betaratio changer 50 may reduce the diameter of the conduit 16 around theregion of the fluid displacement member 18. As shown in FIG. 3A, theperipheral edge 45 of the fluid displacement member 18 has a diameter ofD_(P). Thus, according to Equation 1 above, the meter 12 depicted inFIG. 3A had a beta ratio of:

$\begin{matrix}{\beta_{3A} = \frac{\sqrt{D_{C}^{2} - {D_{P}2}}}{D_{C}}} & (7)\end{matrix}$

By reducing the diameter of the conduit 16, the relationship between thediameter D_(P) of the peripheral edge 45 and the diameter D_(C) of theconduit may be modified to change the beta ratio of the meter 12. Asshown in FIG. 3A and illustrated by arrow 56, the beta ratio changer 50may be inserted into the meter 12 to reduce the inner diameter of theconduit 16.

As shown in FIG. 3B, after installation of the beta ratio changer 50,the inner diameter D_(C) of the conduit 16 is now equal to the innerdiameter of the sleeve 52, i.e., D_(C)=D_(S). Accordingly, the assemblyof the meter 12 and beta ratio changer 50 has a different beta ratiothan the unmodified meter 12. According to Equation 1, the meter 12depicted in FIG. 3B has a beta ratio as follows:

$\begin{matrix}{\beta_{3A} = \frac{\sqrt{D_{S}^{2} - {D_{P}2}}}{D_{S}}} & (8)\end{matrix}$

To enable insertion of the beta ratio changer 50 through the region ofthe conduit 16 that includes the fluid displacement member 18 andsupport, the beta ratio changer 50 may include a slot (illustrated belowin FIG. 4) in the sleeve 52.

FIG. 4 depicts a cross-section of the beta ratio changer 50 inaccordance with an embodiment of the present invention. As discussedabove, the beta ratio changer 50 includes the flanged portion 54 and thesleeve 52 having a slot 58. The slot 58 may extend axially along thelength of the sleeve 52 to enable the flange 54 to be flush with theflange of the body of the meter 12 when the beta ratio changer 50 isinserted into the body of the meter 12. The slot 58 may receive theupstream and downstream ports 28 and 30, enabling the sleeve 52 to beinserted around the ports. Further, the slot 32 ensures fluidcommunication between the port 28 and the interior of the sleeve 52.

The sleeve 52 may define an outer diameter D_(SO) and the inner diameterD_(S), as mentioned above, and define a thickness D_(ST) of the sleeve52. By varying the thickness D_(ST) of the sleeve 52, i.e., by varyingthe inner diameter D_(S), the beta ratio of the meter 12 may beadjusted.

The flange 54 may have an outer diameter D_(F) approximately the same asor less than the outer diameter of the flange of the body 14 of themeter 12. The flange 54 may be of relatively reduced thickness comparedto the thickness of the flange 26 of the body 14 of the meter 12, suchthat when the flange 54 of the beta ratio changer 50 provides minimalincrease of thickness between the meter 12 and other components.

FIG. 5 is a perspective view of the beta ratio changer 50 in accordancewith an embodiment of the present invention. As shown in FIG. 5, thebeta ratio changer 50 may be rotated so that the slot 58 of the sleeve52 is rotated to any desirable position. During installation of the betaratio changer 50, the sleeve 52 may be rotated to rotationally align theslot 58 with the support 19 of the meter 12 having the upstream tap 28and downstream tap 30. During installation, one or more seals, e.g.,o-rings, may be disposed on a first face 60 of the flange 54 and asecond face 62 of the flange 54 to ensure sealing against the flange 26of the meter 12 and any components coupled to the meter 12. In someembodiments, the area ratio changer 50 may be formed from stainlesssteel, carbon steel, or any suitable material. The interior surface ofthe sleeve 52 may be formed to at least a surface finish ofInternational Organization for Standardization (ISO) Standard 1302.

In other embodiments, an area ratio changer may include a sleeve thatextends only over the peripheral edge 45 (cantilevered edge) of thefluid displacement member 18 without extending over the support 15.FIGS. 6A and 6B depict a beta ratio changer 70 having a reduced lengthand the meter 12 in accordance with an embodiment of the presentinvention. The beta ratio changer 70 includes a shortened annular sleeve72 extending axially from a flanged portion 74. The sleeve 72 includesan inner diameter Dss that is smaller than the inner diameter Dc of theconduit 16, enabling reduction of the diameter of the conduit 16 of themeter 12 when the beta ratio changer 70 is installed in the meter 12.However, because the shortened sleeve 72 only extends up to and aroundthe peripheral edge 45 of the fluid displacement member 18, the sleeve72 does not include any slot or other recess.

As discussed above, the peripheral edge 45 of the fluid displacementmember 18 has a diameter of D_(P). Thus, according to Equation 1 above,the meter 12 depicted in FIG. 3A had a beta ratio of:

$\begin{matrix}{\beta_{3A} = \frac{\sqrt{D_{C}^{2} - {D_{P}2}}}{D_{C}}} & (9)\end{matrix}$

As described above, by reducing the diameter of the conduit 16, therelationship between the diameter D_(P) of the peripheral edge 45 andthe diameter Dc of the conduit may be modified to change the beta ratioof the meter 12. As shown in FIG. 6A and illustrated by arrow 76, thebeta ratio changer 70 may be inserted into the meter 12 to reduce theinner diameter of the conduit 16.

As shown in FIG. 6B, once inserted in the conduit 16 of the meter 12,the beta ratio changer 70 only extends up to and around the peripheraledge 45 of the fluid displacement member 18, i.e., that portion of themember 18 defined by the intersection of the upstream frustum 42 anddownstream frustum 44. By extending over the peripheral edge 45, thebeta ratio changer 70 changes the beta ratio of the meter 12 (ascompared to the beta ratio of the configuration depicted in FIG. 6A) byreducing the inner diameter Dc of the conduit 16 over the fluiddisplacement member 18.

As shown in FIG. 6B, after installation of the beta ratio changer 70,the inner diameter D_(C) of the conduit 16 is now equal to the innerdiameter of the sleeve 72, i.e., D_(C)=D_(SS). Accordingly, the assemblyof the meter 12 and beta ratio changer 70 has a different beta ratiothan the unmodified meter 12. According to Equation 1, the meter 12depicted in FIG. 6B has a beta ratio as follows:

$\begin{matrix}{\beta_{3A} = \frac{\sqrt{D_{SS}^{2} - {D_{P}2}}}{D_{SS}}} & (10)\end{matrix}$

FIG. 7 depicts a cross-section of the beta ratio changer 70 inaccordance with another embodiment of the present invention. Asdiscussed above, the beta ratio changer 70 includes the flanged portion74 and a sleeve 72. As noted above in FIGS. 6A and 6B, the sleeve 72 ofthe ratio area changer 70 does not include any slot or other recess inthe sleeve 72. The sleeve 72 may define an outer diameter D_(SO) and theinner diameter D_(SS), as mentioned above, defining a thickness D_(ST)of the sleeve 72. By varying the thickness D_(ST) of the sleeve 72,i.e., by varying the inner diameter D_(SS), the beta ratio of the meter12 may be adjusted.

The flange 74 may have an outer diameter D_(F) approximately the same asor less than the outer diameter of the flange 26 of the body 14 of themeter 12. The flange 74 may be of relatively reduced thickness comparedto the thickness of the flange 26 of the body 14 of the meter 12, suchthat when the flange of the beta ratio changer 70 provides minimalincrease of thickness between the flange 26 and other components.

FIG. 8 is a perspective view of the beta ratio changer 70 of FIG. 7 inaccordance with an embodiment of the present invention. Duringinstallation, one or more seals, e.g., o-rings, may be disposed on afirst face 78 of the flange 74 and a second face 80 of the flange 74 toensure sealing against the flange 26 of the meter 12 and any componentscoupled to the meter 12. In some embodiments, the beta ratio changer 70may be formed from stainless steel, carbon steel, or any suitablematerial. The interior wall of the sleeve 72 may be formed to at least asurface finish of ISO Standard 1302. The beta ratio changer 70 having areduced sleeve length may be cheaper and easier to manufacture than thebeta ratio changer 50 shown above in FIGS. 3-5. For example, manufactureof the beta ratio changer 70 may use less material and require lessmachining than the beta ratio changer 50 discussed above in FIGS. 3-5.

The beta ratio changers 50 and 70 described above may provide a 10%,20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or any other percentage, changeto the beta ratio of the flow meter 12. In some embodiments, one or aplurality of beta ratio changers 50 or 70 may be packaged with the meter12 and sold as a single unit. For example, each included beta ratiochanger 50 or 70 may have a different sleeve thickness and innerdiameter, allowing selection among multiple beta ratios. In such anembodiment, the meter 12 may be calibrated for each included beta ratiochanger 50 or 70, thus expanding the usable range of the meter 12 wheninstalled in the field. By installing, removing, or interchangingvarious area ratio changers, the beta ratio of the meter 12 may bechanged in the field without replacement of the meter 12. In otherembodiments, the area ratio changers 50 and/or 70 may be sold as aretrofit kit to enable installation on existing meters. In theseembodiments, the beta ratio changer may enable changing of the betaratio changer of existing meters installed in the field withoutreplacement of the entire meter assembly.

In other embodiments, an area ratio changer as described above may beused with any metering devices that use a pressure measurement element.FIG. 9A depicts use of an area ratio changer 80 with a flow meter 81having a Pitot tube 82 in accordance with an embodiment of the presentinvention. The Pitot tube 82 may be installed in a structure 84, e.g., apipe, having a conduit 86. As shown in FIG. 9A, fluid may flow in theconduit 86 in the direction illustrated by arrows 88. The Pitot tube 82may include one or more holes 90 to enable measurement of the stagnationpressure of the fluid. The Pitot tube 82 may be coupled to a manifold 92which may provide fluid communication to the static pressure measured bythe Pitot tube 82 and/or fluid communication to other portions of theconduit 86, such as upstream or downstream from the Pitot tube 82.

In certain embodiments, the Pitot tube device 82 may be designed for aspecific range of flow rates and/or type of fluid. In such anembodiment, any reduction in flow of the fluid through the conduit 86may result in reduced accuracy or failure of the meter 81 due to thereduced flow range. In such an embodiment, the area ratio changer 80 maybe inserted into the conduit 86 to reduce the interior volume of theconduit and increase the flow rate of the fluid, enabling meteringcapability by the meter 81.

As described above, the area ratio changer 80 may include a sleeve 94and a flange 96 to enable installation into the conduit 86. The sleeve94 may include an inner diameter Ds less than the inner diameter D_(C)of the conduit 86. The area ratio changer 80 may include a slot, similarto the embodiment depicted above in FIG. 3-5, to enable insertion aroundthe Pitot tube 82, reducing the diameter in portions of the conduit 86upstream and downstream from the conduit 16. The area ratio changer 80may be installed in the conduit 86 as indicated by arrow 100 of FIG. 9A.

FIG. 9B depicts the installed area ratio changer 80 in the meter 81 inaccordance with an embodiment of the present invention. As shown in FIG.9B, the sleeve 94 extends into the portions of the conduit 86 downstreamand upstream of the Pitot tube 82. Thus, after installation of the arearatio changer 80, the conduit 86 has a reduced diameter equal to theinner diameter D_(S) of the sleeve 94 (i.e., D_(C)=D_(S)) downstream andupstream of the Pitot tube 82. By reducing the inner diameter of theconduit 86, the velocity of the fluid in the conduit 86 may be increasedto within a range measurable by the meter 81. The inner diameter of thesleeve 94 of the area ratio changer 80 may be selected to increase theflow velocity to any desirable range, thus enabling functionality of themeter 81 and Pitot tube 82. Advantageously, installation of the arearatio changer 80 avoids removal and replacement of the meter 81 andpurchase and installation of a replacement meter.

FIGS. 10A and 10B depict use of an area ratio changer 110 with a vortexmeter 112 in accordance with another embodiment of the presentinvention. The vortex meter 112 may include a buff body 114, installedin a structure 116, e.g., a pipe, having a conduit 118. The buff body114 may be coupled to a mechanical or electrical measuring device 120,e.g., a gauge, through a flange 122. As shown in FIG. 10A, fluid mayflow in the conduit 118 in the direction illustrated by arrows 124. Thebuff body 114 may induce vortices in the fluid as it flows through theconduit 118, resulting in a vortex trail over the bluff body 114. Aswill be appreciated, the vortex meter 112 may determine the flow rate ofthe fluid in the conduit 118 based on the relationship between thenumber of vortices created and the flow rate of the fluid.

In certain embodiments, the ability of the bluff body 114 to producevortices may be negatively affected by a fluid having a low flowvelocity or low Reynolds number. The lowered flow velocity or lowerReynolds number fluid may result in erratic and/or inaccurate outputfrom the vortex meter 112. In such an embodiment, the area ratio changer110 may be inserted into the conduit 118 to reduce the interior volumeof the conduit and increase the flow rate of the fluid, enablingmetering capability by the meter 81.

As described above, the area ratio changer 110 may include a sleeve 126and a flange 128 to enable installation into the conduit 118. The sleeve126 may an inner diameter D_(S) less than the inner diameter D_(C) ofthe conduit 118. The area ratio changer 110 may include a slot, similarto the embodiment depicted above in FIG. 3-5, to enable insertion arounda stem 127 of the buff body 114. Thus, the area ratio changer 110 may beused to reduce the diameter D_(C) of the conduit 118 upstream anddownstream from the buff body 114. The area ratio changer 110 may beinstalled in the conduit 118 as indicated by arrow 132 of FIG. 9A.

FIG. 10B depicts the installed area ratio changer 110 in the meter 112in accordance with an embodiment of the present invention. As shown inFIG. 10B, the sleeve 126 extends into the portions of the conduit 118downstream and upstream of the buff body 114. Thus, after installationof the area ratio changer 110, the conduit 118 has a diameter D_(C)equal to the inner diameter D_(S) of the sleeve 126 (i.e., D_(C)=D_(S))in those portions of the conduit 16 downstream and upstream of the buffbody 114. By reducing the inner diameter of the conduit 118, theReynolds number (of flow velocity) of the fluid flowing in the conduit118 may be increased to within a range more suitable for effectivevortex induction by the buff body 114. The increased Reynolds numberand/or flow velocity of the fluid may enable easier creation of vorticesas the fluid flows over the buff body 114, increasing the effectivenessof the vortex meter 114. Advantageously, as mentioned above,installation of the area ratio changer 110 avoids removal andreplacement of the meter 112 and purchase of the replacement meter.

In other embodiments, a beta/area ratio changer may be formed from anerosion-resistant material to protect the conduit of a flow meter. FIG.11 depicts a beta ratio changer 120 formed from an erosion-resistantmaterial and installed in the differential pressure flow meter 12 asdescribed above in FIGS. 1-3. In addition to changing the beta ratio ofthe meter 12, as described above, the beta ratio changer 120 may protectan inner wall 122 of the conduit 16 from erosion by the fluid flowing inthe conduit 16 of the meter 12. In some embodiments, the fluid may havephysical or chemical properties that may erode or otherwise damage themeter body 14, such as by physically or chemically eroding the innerwall 122. For example, the fluid may include particles or other solidsthat could erode or otherwise damage the inner wall 122. As the fluidflows through the conduit 16, such as in the direction indicated byarrow 20, the beta ratio changer 120 may protect the inner wall 122 ofthe conduit 16 from eroding properties of the fluid. Thus, the termerosion-resistant may encompass both protection from physical erosionand chemical resistance.

In some embodiments, the erosion-resistant beta ratio changer 120 may beformed from stellite, talonite, tungsten carbide, cemented carbide, orany other suitable material. In other embodiments, the beta ratiochanger 120 may be formed from other carbides, or ceramics. As shown inFIG. 11, in some embodiments, the beta ratio changer 120 may extendthrough the length of the conduit 16, similar to the beta ratio changer50 described above in FIGS. 1-3. However, an erosion-resistant arearatio changer may be used in any of the applications described above,such as the area ratio changer 72 described above in FIGS. 6-8, the arearatio changer 94 for a flow meter 82 having a Pitot tube 82 describedabove in FIGS. 9A and 9B, and the area ratio changer 126 for a vortexmeter 112 described above in FIGS. 10A and 10B. Any of theabove-described area ratio changers may be formed from anerosion-resistant material such as stellite, talonite, tungsten carbide,cemented carbide, or any other suitable material.

In other embodiments, an erosion-resistant insert may be used tomaintain the beta ratio or area ratio of a flow meter during operation.The erosion-resistant insert may prevent erosion or other damage of themeter body and prevent changes in the beta ratio (or area ratio) orother properties of the meter that could affect performance of themeter. In such an embodiment, the conduit of the meter body may bemachined to accommodate the insert.

FIGS. 12 and 13 depict use of an erosion-resistant insert in thedifferential pressure flow meter 12 described above in accordance withan embodiment of the present invention. As described above, thedifferential pressure flow meter 12 may includes the meter body 14having the conduit 16 through which fluid may flow. The fluiddisplacement member 18 may be centrally disposed in the conduit 16 andsuspended from the conduit 16 via the support 19. Fluid may flow throughthe conduit 16 and over the fluid displacement member 18 in thedirection indicated by arrows 20. As also described above, the meterbody 14 may include the upstream pressure tap 28 in fluid communicationwith the conduit 16 and the downstream pressure tap 30 in fluidcommunication with the interior of the fluid displacement member 18 andthe downstream portion of the conduit 16 through hollow region 32. Insome embodiments, as noted above, the meter may be coupled to a valvemanifold 34 and various other components, such as a transmitter 26 andcomputer 38.

As noted above, the conduit 16 may have a diameter D_(C) and theperipheral edge 45 of the fluid displacement member 18 has a diameter ofD_(P). As depicted in FIG. 12, a portion of the meter body 14 may bemachined to form a recess, e.g. annular recess 130, in the inner walls122 of the conduit 16. The annular recess 130 may have a diameter ofD_(R). The annular recess 130 is formed to receive an erosion-resistantinsert as depicted in FIG. 13. The diameter D_(R) of the annular recess130 may be selected to ensure that the erosion-resistant insertmaintains the original diameter D_(C) of the conduit 16.

FIG. 13 depicts the meter of FIG. 12 with an erosion-resistant insert132 installed in the meter body 14 in accordance with an embodiment ofthe present invention. As seen in FIG. 13, the insert 132 may beinstalled in the recess 130 formed in the conduit 16. Additionally, theinsert 132 has a diameter D_(I) equal to the diameter D_(C) of theconduit 16. Thus, when installed in the recess 130, the insert 132maintains the diameter D_(C) of the conduit 16 and maintains theoriginal beta ratio or area ratio of the 12 (i.e., by maintaining thediameter D_(C) of the conduit 16 relative to the diameter D_(P) of theperipheral edge 45 of the fluid displacement member 18). Theerosion-resistant insert 132 protects the inner walls 122 of the conduitfrom erosion by the fluid flowing through the meter 12. For example, asmentioned above, in some embodiments the fluid may have physical and/orchemical properties that could erode or otherwise damage the inner walls122 of the conduit 16. The insert 132 may be formed from stellite,talonite, tungsten carbide, or any suitable material that provides thedesired erosion-resistance for the meter. In other embodiments, theinsert 132 may be formed from other carbides, or ceramics

The erosion-resistant insert 132 and corresponding recess 130 may beformed at different lengths along the meter body 14. For example, in theembodiment depicted in FIG. 13, the insert 132 and the recess 130 mayhave a length L1 extending up to the support 19. In other embodiments,the insert 132 may have a length L2 corresponding to all orsubstantially all of the length of the conduit 16. In such embodiments,the insert 132 may be constructed similar to the beta ratio changer 50depicted above in FIGS. 4 and 5 to include a slot to accommodate thesupport 19. In such an embodiment, the recess 130 may be formed in boththe upstream portion and downstream portion of the meter body 14 (e.g.,on both side of the fluid displacement member 18). In other embodiments,the length of the insert 132 and the recess 130 may be between L1 andL2. Further, in some embodiments, the recess 130 may be formed at alength slightly greater than the length of the insert 132 to provide foreasier installation of the insert 132.

FIG. 14 depicts a cross-section of the erosion-resistant insert 132 ofFIG. 13 in accordance with an embodiment of the present invention. Theinsert 132 may include a flanged portion 134 and a sleeve 136. Thesleeve 136 may define the outer diameter D_(R) and the inner diameterD_(I), as mentioned above, defining a thickness D_(RI) of the sleeve136. As described above, the inner diameter D_(I) of the sleeve mayequal the inner diameter D_(C) of the conduit 16. Thus, the thickness ofthe sleeve D_(RI) is equal to the thickness of the recess (D_(R)-D_(C)).When installed in the recess 130, the insert 132 provides the originaldiameter D_(C) of the conduit, thus maintaining the original beta ratioor area ratio of the meter 12. As also discussed above, the sleeve mayhave a length L1 equal to or substantially equal to the length of therecess L1.

The flange 134 may have an outer diameter D_(F) approximately the sameas or less than the outer diameter of the flange 26 of the body 14 ofthe meter 12. The flange 134 may be of relatively reduced thicknesscompared to the thickness of the flange 26 of the body 14 of the meter12, such that when the insert 132 is installed in the conduit 16 theflange 134 provides minimal increase of thickness between the flange 26and other components. In some embodiments, the insert 132 may be securedby the flange 134 disposed between the flange 26 and another componentcoupled to the meter 12. In some embodiments, the insert 132 may becoupled to the meter 12 by fasteners such as bolts or screws. In yetother embodiments, the insert 132 may be threadingly coupled to themeter 12.

FIG. 15 is a perspective view of the erosion-resistant insert 132 ofFIG. 13 in accordance with an embodiment of the present invention.During installation, one or more seals, e.g., o-rings, may be disposedon a first face 138 of the flange 134 and a second face 140 of theflange 134 to ensure sealing against the flange 26 of the meter 12 andany components coupled to the meter 12. As mentioned above, the insert132 may be formed from stellite, talonite, tungsten carbide, or othersuitable erosion-resistant materials. In some embodiments, both thesleeve 136 and the flange 134 may be formed from the erosion-resistantmaterial or only the sleeve 136 may be formed from the erosion-resistantmaterial. In some embodiments, the interior wall of the sleeve 136 maybe formed to at least a surface finish of ISO Standard 1302.

In other embodiments, as mentioned above, the insert may extend to alength L2. FIG. 16 depicts a cross-section and FIG. 17 depicts aperspective view of an erosion-resistant insert 142 having a length L2in accordance with an embodiment of the present invention. As discussedabove, the insert 142 includes a flanged portion 144 and a sleeve 146.The sleeve 146 may define an outer diameter D_(R) and the inner diameterD_(I), as mentioned above, defining a thickness D_(RI) of the sleeve146. As described above, the inner diameter D_(I) of the sleeve 146 maybe equal to the inner diameter D_(C) of the conduit 16, ensuring thatthe insert 142 maintains the diameter of the conduit 16. As alsodiscussed above, the sleeve may have a length L2 equal to about thelength of a recess formed in the conduit 16.

The insert 142 having a longer length L2 may also include a slot 148.The slot 148 may extend axially along the length of the sleeve 146 andaccommodate the support 19 to enable the flange 144 to be flush with theflange of the body of the meter 12 when the insert is inserted into thebody of the meter 12. The slot 148 may receive the upstream anddownstream ports 28 and 30, enabling the sleeve 146 to be insertedaround the ports. Further, the slot 148 ensures fluid communicationbetween the port 28 and the conduit 16. The flange 144 may have an outerdiameter D_(F) approximately the same as or less than the outer diameterof the flange 26 of the body 14 of the meter 12. Again, the flange 144may be of relatively reduced thickness compared to the thickness of theflange 26 of the body 14 of the meter 12. In some embodiments, theinsert 142 may be secured by the flange 144 disposed between the flange26 and another component coupled to the meter 12. In some embodiments,the insert 142 may be coupled to the meter 12 by fasteners such as boltsor screws. In yet other embodiments, the insert 142 may be threadinglycoupled to the meter 12.

As also noted above, the flange 144 may include one or more seals, e.g.,o-rings, disposed on a first face 150 of the flange 144 and a secondface 152 of the flange 146 to ensure sealing against the flange 26 ofthe meter 12 and any components coupled to the meter 12. The insert 142may be formed from stellite, talonite, tungsten carbide, or othersuitable erosion-resistant materials. In other embodiments, the insert142 may be formed from other carbides, or ceramics. In some embodiments,both the sleeve 146 and the flange 144 may be formed from theerosion-resistant material or only the sleeve 146 may be formed from theerosion-resistant material. In some embodiments, the interior wall ofthe sleeve 136 may be formed to at least a surface finish of ISOStandard 1302.

In other embodiments, an erosion-resistant insert may used to protectthe inner walls of other meters and maintain the inner diameter of aconduit of such meters. For example, an erosion-resistant insert may beused in any of the applications described above, such as the flow meter82 having a Pitot tube 82 described above in FIGS. 9A and 9B, and thevortex meter 112 described above in FIGS. 10A and 10B. Anerosion-resistant insert may be installed in the manner described above,such as by machining a recess in a conduit of a meter and inserting theinsert. Such erosion-resistant inserts may also be formed from anerosion-resistant material such as stellite, talonite, tungsten carbide,cemented carbide, other carbides, ceramics, or any other suitablematerial.

FIG. 18 depicts a process 160 for installing and using anerosion-resistant insert in a fluid measurement device, such as a flowmeter, in accordance with an embodiment of the present invention.Initially, a flow meter 160 may be provided (block 162). The meter maybe a new meter, or the meter may be an existing meter and theerosion-resistant insert provided as a part of a retrofit kit. A recessmay be machined in the conduit of the meter body to receive the insert(block 164). As mentioned above, the recess may be machined any one ofdifferent lengths to receive an insert. The insert may be installed inthe conduit of the meter body to maintain the diameter D_(C) of theconduit 16 (block 166). After insertion, the meter may be calibrated(block 168). Finally, the meter may be operated with theerosion-resistant interior of the conduit provided by the insert (block170).

While the invention may be susceptible to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and have been described in detail herein.However, it should be understood that the invention is not intended tobe limited to the particular forms disclosed. Rather, the invention isto cover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the followingappended claims.

The invention claimed is:
 1. A system, comprising: a flow measurementdevice; an erosion-resistant insert configured to removably couple tothe flow measurement device, the erosion-resistant insert comprising: aflanged portion; and a sleeve portion configured to extend into a fluidconduit of the flow measurement device and maintain a property of theflow measurement device, wherein the sleeve portion comprises anerosion-resistant material.
 2. The system of claim 1, wherein the sleeveportion has an inner diameter equal to a first inner diameter of thefluid conduit.
 3. The system of claim 1, wherein the property comprisesa beta ratio of the flow measurement device.
 4. The system of claim 1,wherein the flow measurement device comprises a fluid displacementmember defines having a peripheral edge separating an upstream slopingsurface from a downstream sloping surface.
 5. The system of claim 4,wherein the erosion-resistant insert extends at least around theperipheral edge of the fluid displacement member.
 6. The system of claim4, wherein the erosion-resistant insert extends around the fluiddisplacement member.
 7. The system of claim 1, wherein the flowmeasurement device comprises a Pitot tube.
 8. The system of claim 5,wherein the erosion-resistant insert extends around the Pitot tube. 9.The system of claim 1, wherein the flow measurement device comprises avortex meter.
 10. The system of claim 9, wherein the vortex metercomprises a buff body and the erosion-resistant insert extends aroundthe buff body.
 11. The system of claim 1, wherein the erosion-resistantmaterial comprises stellite, tungsten carbide, or cemented carbide. 12.A system, comprising: an erosion-resistant insert for a flow measurementdevice, comprising: a flanged portion; and a sleeve portion extendingaxially from the flanged portion, wherein the sleeve portion isconfigured to insert into a fluid conduit of the flow measurement deviceand maintain a property of the flow measurement device.
 13. The systemof claim 12, wherein the property comprises a beta ratio of the flowmeasurement device.
 14. The system of claim 12, wherein the sleeveportion comprises stellite, tungsten carbide, or cemented carbide. 15.The system of claim 12, wherein the sleeve portion comprises an axialslot.
 16. The system of claim 12, wherein the flanged portion comprisesstellite, tungsten carbide, or cemented carbide.
 17. A method,comprising: inserting an erosion-resistant insert into a recess of aconduit of a flow measurement device, wherein the insert comprises asleeve portion and a flange portion, wherein the sleeve portioncomprises an erosion-resistant material.
 18. The method of claim 17,comprising maintaining a beta ratio of the flow measurement device byinserting the erosion-resistant insert into the recess.
 19. The methodof claim 17, comprising measuring the flow rate of a fluid flowingthrough the conduit of the flow measurement device.
 20. The system ofclaim 19, wherein the fluid comprises oil, natural gas, or steam. 21.The system of claim 12, wherein the erosion-resistant insert is rigid.22. The system of claim 12, wherein the sleeve portion is rigid, and thesleeve portion is formed from an erosion-resistant material.
 23. Thesystem of claim 12, wherein the sleeve portion is formed from theerosion-resistant material.